Variable resistance exercise apparel

ABSTRACT

Described herein relates to a variable resistance exercise system and method of providing resistance to a target muscle group at a predetermined joint of a user. The variable resistance exercise system may be configured to provide speed-dependent, bi-directional, and/or variable resistance at the predetermined joint. Accordingly, the variable resistance exercise system, may target the predetermined joint (e.g., an elbow) and/or provide resistance against the ability of the user to flex the targeted muscle group about the predetermined joint, optimizing the effectiveness and safety of resistance training, allowing the promotion of muscle hypertrophy of the user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional application claims the benefit of U.S. Provisional Application No. 63/343,302 entitled “VARIABLE RESISTANCE EXERCISE APPAREL” filed May 18, 2022 by the same inventors, all of which is incorporated herein by reference, in its entirety, for all purposes.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates, generally, to resistance training equipment. More specifically, it relates to an apparatus and method for providing adjustable, speed-dependent and quantifiable resistance to at least one muscle group during flexion and extension of a body joint of a user.

2. Brief Description of the Prior Art

Muscle performance and quality levels have several determining factors, such as muscle mass, density, composition, and neural activation. Individually and collectively, these determining factors influence a user's ability to perform various activities of daily living (ADLs). Additionally, muscle disorders, often triggered by genetic issues, injury, overuse, or even nerve diseases, can cause the affected muscles to gradually degrade and lose muscle mass, leading to severe muscle atrophy. The subsequent muscle loss may lead to many complications such as motor control issues of the limbs affected to perform ADLs or malfunctioning of the cardiovascular or circulatory system.

Currently known muscle performance techniques have focused on the efficacy of resistance training in regaining muscle mass and density. It has been shown that resistance training may enhance muscle strength per unit muscle mass—the amount of force that muscle can exert to resist an unyielding resistance in one maximal contraction—by 22% in the user and help patients with Parkinson's disease to regain muscle strength and control. Additionally, it has been shown that resistance training increases the cross-sectional area of the muscle, commonly referred to as muscle hypertrophy, due to growth in individual muscle fiber diameter and/or the number of muscle fibers. Such an increase in the cross-sectional area of the muscle directly relates to muscle strength.

Resistance training induces physiologic muscle adaptation, an adaptation of the muscle fiber and the nervous system to enhance motor unit recruitment and promote greater muscle activation. Moreover, a user benefits from resistance training through an increase in capillary density in the surrounding muscle area, permitting more accessible transportation of nutrients required for muscle movement. The results support the necessity and effectiveness of resistance training for individuals with muscle atrophy to help them maintain or regain muscle mass and density.

The currently known resistance training practices focus on weightlifting. While weightlifting can be very effective in achieving muscle hypertrophy, exercising with weighted equipment could be challenging and sometimes unsafe if muscle mass and strength are very low. As such, resistance training with reduced/variable load (such as using resistance bands or wearable devices) would be suitable. In fact, a resistance band can increase the duration and/or repetition of muscle training before fatigue accumulates, which can be safer and more effective than weightlifting. This method, even though it is the most viable resistance training method for the user and muscle atrophy patients, has some limitations: 1) resistance is proportional to the amount of stretch of the material, thus, the highest resistance is obtained when the joints are fully extended, which can exert undesirable strain to body joints or muscles; 2) provides only unidirectional resistance, engaging either flexor or extensor muscle groups for a given movement; 3) affects entire limb(s) across multiple joints which may not be appropriate for use by individuals with pre-existing musculoskeletal injuries or conditions; 4) does not allow the user to exercise specific muscle groups; and 5) cannot adjust or quantify the resistance force exerted on the body.

Recent advances in resistance band training include wearable devices, however, the wearable devices function substantially similar to the resistance band, such that elastic bands or cables are connected between the torso (e.g., pelvis) and distal part of the body (e.g., wrist or ankle). Accordingly, the limitations associated with the resistance band apply to these wearable devices. While exoskeletons and powered wearable devices have been presented as potential alternatives to resistance bands, the bulk, weight, and power supply requirements for these powered wearable devices increase the impracticality and uselessness of the devices.

Accordingly, what is needed is a safe, easy-to-use, and portable exercise apparel that allows the user to effectively focus on one muscle group by using variable resistance at a single joint of the user. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the field of this invention how the shortcomings of the prior art could be overcome.

SUMMARY OF THE INVENTION

The long-standing but heretofore unfulfilled need, stated above, is now met by a novel and non-obvious invention disclosed and claimed herein. In an aspect, the present disclosure pertains to a variable resistance exercise system. In an embodiment, the variable resistance exercise system may comprise the following: (a) at least one brace configured to conform to an appendage of a user; and (b) an exercise apparatus configured to be disposed about a portion of a surface of the at least one brace aligning with a predetermined joint of a user, the exercise apparatus being in mechanical communication with the at least one brace, wherein the exercise apparatus further comprises: (i) a base; (ii) a plurality of pulleys configured to be temporarily affixed to the base; (iii) at least one belt in mechanical communication with the plurality of pulleys, such that the at least one belt may be configured to encompass the plurality of pulleys; and (iv) a plurality of mechanical dampers disposed about at least a portion of the plurality of pulleys. In this embodiment, the plurality of mechanical dampers may be configured to provide a damping coefficient upon the plurality of pulleys, automatically increasing a force required to translate the at least one belt about the plurality of pulleys.

In some embodiments, the exercise apparatus of the variable resistance exercise system may further comprise a plurality of exercise keys, such that each one of the plurality of exercise keys may be configured to be disposed within an opening of each respective mechanical damper of the plurality of mechanical dampers. In addition, in these other embodiments, when at least one of the plurality of exercise keys is disposed within at least one of the plurality of mechanical dampers, the at least one mechanical damper may be configured to provide a damping coefficient, automatically increasing a force required to operate the plurality of pulleys.

In some embodiments, the pulley system may comprise a triangle formation. In some embodiments, each of the plurality of pulleys may comprise at least one ball bearing, such that the at least one ball bearing may be configured to allow the plurality of pulleys to rotate about the base of the exercise apparatus.

In some embodiments, the plurality of mechanical dampers may comprise the following, including but not limited to a small mechanical damper, a medium mechanical damper, and/or a large mechanical damper. In addition, the plurality of exercise keys may comprise the following, including but not limited to a small exercise key, a medium exercise key, and/or a large exercise key. In this manner, in these other embodiments, the small mechanical damper may be configured to provide a lower damping coefficient than the medium mechanical damper and/or the large mechanical damper. As such, the medium mechanical damper may be configured to provide a damping coefficient greater than the smaller damper and less than the larger damper.

In some embodiments, the variable resistance exercise system may further comprise the following: (a) a computing device having at least one processor communicatively coupled to at least one sensor, such that the at least one sensor may be disposed about at least one portion of the at least one brace, and/or the exercise apparatus; and (b) an electronic circuity disposed within the base of the exercise apparatus, such that the electronic circuity may be configured to selectively supply the electronic current to the computing device and/or the at least one sensor. In these other embodiments, when the user is engaged with the exercise apparatus, the at least one sensor may be configured to detect exercise data. As such, the exercise data may comprise the following, including but not limited to a total amount of exertion by a targeted muscle group disposed about the predetermined joint of the user during the plurality of exercises, a weight of the user, a total amount of mechanical dampers comprising an exercise key, a height of the user, an age of the user, and/or a gender of the user. In addition, in these other embodiments, subsequent to receiving the exercise data from the at least one sensor, the at least one processor may be configured to cause the electronic circuity to supply an electric current to a display device associated with the computing device, such that the display device may be configured to provide the exercise data to the user.

Moreover, another aspect of the present disclosure pertains to an exercise apparatus for providing variable resistance during an exercise. In an embodiment, the exercise apparatus may comprise the following: (a) a base; (b) a plurality of pulleys configured to be temporarily affixed to the base; (c) at least one belt in mechanical communication with the plurality of pulleys, such that the at least one belt may be configured to encompass the plurality of pulleys; and (d) a plurality of mechanical dampers disposed about at least a portion of the plurality of pulleys. In this embodiment, the plurality of mechanical dampers may be configured to provide a damping coefficient upon the plurality of pulleys, automatically increasing a force required to translate the at least one belt about the plurality of pulleys.

In some embodiments, the exercise apparatus of the variable resistance exercise system may further comprise a plurality of exercise keys, wherein the each one of the plurality of exercise keys is configured to be disposed within an opening of each respective mechanical damper of the plurality of mechanical dampers. In addition, in these other embodiments, when at least one of the plurality of exercise keys is disposed within at least one of the plurality of mechanical dampers, the at least one mechanical damper may be configured to provide a damping coefficient, automatically increasing a force required to operate the plurality of pulleys.

In some embodiments, the pulley system may comprise a triangle formation. In some embodiments, each of the plurality of pulleys may comprise at least one ball bearing, such that the at least one ball bearing may be configured to allow the plurality of pulleys to rotate about the base of the exercise apparatus.

In some embodiments, the plurality of mechanical dampers may comprise the following, including but not limited to a small mechanical damper, a medium mechanical damper, and/or a large mechanical damper. In addition, the plurality of exercise keys may comprise the following, including but not limited to a small exercise key, a medium exercise key, and/or a large exercise key. In this manner, in these other embodiments, the small mechanical damper may be configured to provide a lower damping coefficient than the medium mechanical damper and/or the large mechanical damper. As such, the medium mechanical damper may be configured to provide a damping coefficient greater than the smaller damper and less than the larger damper.

Furthermore an additional aspect of the present disclosure pertains to a method of providing a variable resistance to a targeted muscle group at a predetermined joint of a user during a plurality of exercises. In an embodiment, the method may comprise the following: (a) affixing a variable resistance exercise system to the user, the variable resistance exercise apparatus comprising: (i) at least one brace configured to conform to an appendage of a user; and (ii) an exercise apparatus configured to be disposed about a portion of a surface of the at least one brace aligning with a predetermined joint of a user, the exercise apparatus being in mechanical communication with the at least one brace, wherein the exercise apparatus further comprises: (A) a base; (B) a plurality of pulleys configured to be temporarily affixed to the base; (C) at least one belt in mechanical communication with the plurality of pulleys, such that the at least one belt may be configured to encompass the plurality of pulleys; and (D) a plurality of mechanical dampers disposed about at least a portion of the plurality of pulleys, such that the plurality of mechanical dampers may be configured to provide a damping coefficient upon the plurality of pulleys, automatically increasing a force required to translate the at least one belt about the plurality of pulleys; (b) engaging, via at least one of a plurality of exercises keys configured to be disposed within an opening of at least one respective mechanical damper of the plurality of mechanical dampers, at least one of the plurality of mechanical dampers, such that the at least one of the plurality of mechanical dampers may be configured to provide a damping coefficient on at least one of the plurality of pulleys, automatically increasing the required resistance to translate the at least one belt about the plurality of pulleys; and (c) performing, via variable resistance exercise system, a plurality of exercises requiring flexion and/or extension of the targeted muscle group, such that a resistive force may be provided to the targeted muscle group based on a total amount of engaged mechanical dampers.

In some embodiments, the variable resistance exercise system, further comprises: (i) a computing device having at least one processor communicatively coupled to at least one sensor, such that the at least one sensor may be disposed about at least one portion of the at least one brace, the exercise apparatus, or both; and (ii) an electronic circuity disposed within the base of exercise apparatus, such that the electronic circuity may be configured to selectively supply the electronic current to the computing device and/or the at least one sensor.

Additionally, in these other embodiments, the method may further comprise the steps of: (a) transmitting, via the at least one sensor, exercise data to a display device associated with the computing device of the variable resistance exercise system; and (b) displaying, via the at least one processor, the exercise data on the display device, such that the display device may be configured to provide the exercise data to the user via visual means, auditory means and/or tactile means.

In some embodiments, the variable resistance exercise system may be a bi-directional (e.g., the plurality of pulleys may translate forwards and/or backwards without limitation), speed-dependent, and/or variable resistance device capable of providing different levels of resistance at the targeted joint via simple manual adjustments. In this manner, The variable resistance exercise system may be optimized to increase the effectiveness and safety of resistance training, allowing the promotion of muscle hypertrophy in the user.

Additionally, the variable resistance exercise system may be used in rehabilitation and physical therapy, providing a user, who is in need of specialized training regimens, with a safer, tunable, quantifiable resistance training platform. Additionally, the variable resistance exercise system may be configured to be a replacement and/or substitution of existing devices for use in muscle strength and/or resistance training for muscle hypertrophy. In these other embodiments, the variable resistance exercise system may also be configured to be speed-dependent, such that a user must maintain a certain rate of flexion to complete the exercise. Moreover, the variable resistance exercise system may be configured to function bi-directionally, such that a user may receive resistance in multiple directions, allowing the user to exert torque through multiple muscle groups at the targeted joint.

Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not restrictive.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the disclosure set forth hereinafter and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective top view of a pulley system of a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 2 is a perspective bottom view of a pulley system of variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 3 is a cross-sectional view of a pulley system of variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 4 is a perspective view of a variable resistance exercise system comprising at least one mechanical dampener disposed on an arm of a user, according to an embodiment of the present disclosure.

FIG. 5 is a perspective view of a variable resistance exercise system comprising at least one mechanical dampener disposed on a leg of a user, according to an embodiment of the present disclosure.

FIG. 6A is a perspective view of a variable resistance exercise system in a starting position for a maximum voluntary bicep contraction of a user, according to an embodiment of the present disclosure.

FIG. 6B is a perspective view of a variable resistance exercise system in an end position for a maximum voluntary bicep contraction of a user, according to an embodiment of the present disclosure.

FIG. 7A is a perspective view of a variable resistance exercise system in a start position for a maximum voluntary triceps contraction of a user, according to an embodiment of the present disclosure.

FIG. 7B is a perspective view of a variable resistance exercise system in an end position for a maximum voluntary triceps contraction of a user, according to an embodiment of the present disclosure.

FIG. 8 is a graph illustrating a normalized bicep peak EMG of eight resistance configurations, according to an embodiment of the present disclosure.

FIG. 9 is a graph illustrating a normalized bicep integrated EMG of eight resistance configurations, according to an embodiment of the present disclosure.

FIG. 10 is a plot illustrating a normalized bicep EMG linear envelope of eight resistance configurations, according to an embodiment of the present disclosure.

FIG. 11 is a graph illustrating a normalized triceps peak EMG of eight resistance configurations, according to an embodiment of the present disclosure.

FIG. 12 is a graph illustrating a normalized triceps integrated EMG of eight resistance configurations, according to an embodiment of the present disclosure.

FIG. 13 is a plot illustrating a normalized triceps EMG linear envelope of eight resistance configurations, according to an embodiment of the present disclosure.

FIG. 14 is an exemplary diagram depicting assessment sessions during a predetermined training session utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 15 is a graph illustrating dynamometer testing of an average peak torque (Nm) during elbow flexion while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 16 is a graph illustrating dynamometer testing of an average peak torque (Nm) during elbow extension while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 17 is a graph illustrating dynamometer testing of an average peak torque/skeletal muscle mass (Nm/Kg) during elbow flexion while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 18 is a graph illustrating dynamometer testing of an average peak torque/skeletal muscle mass (Nm/Kg) during elbow extension exercise while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 19 is a graph illustrating dynamometer testing of a peak torque/skeletal muscle mass (Nm/Kg) of elbow isometric torque during elbow flexion and/or elbow extension while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 20 is a graph illustrating dynamometer testing of an average peak torque (Nm) during knee flexion while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 21 is a graph illustrating dynamometer testing of an average peak torque (Nm) during knee extension while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 22 is a graph illustrating dynamometer testing of an average peak torque/skeletal muscle mass (Nm/Kg) during knee flexion while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 23 is a graph illustrating dynamometer testing of an average peak torque/skeletal muscle mass (Nm/Kg) during knee extension exercise while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 24 is a graph illustrating dynamometer testing of a peak torque/skeletal muscle mass (Nm/Kg) of knee isometric torque during knee flexion and/or knee extension while utilizing a variable resistance exercise system, according to an embodiment of the present disclosure.

FIG. 25 is an exemplary flow chart depicting the steps of a method of exercising a muscle group of a user using a variable resistance exercise system, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part thereof, and within which are shown by way of illustration specific embodiments by which the invention may be practiced. It is to be understood that one skilled in the art will recognize that other embodiments may be utilized, and it will be apparent to one skilled in the art that structural changes may be made without departing from the scope of the invention. Elements/components shown in diagrams are illustrative of exemplary embodiments of the disclosure and are meant to avoid obscuring the disclosure. Any headings, used herein, are for organizational purposes only and shall not be used to limit the scope of the description or the claims. Furthermore, the use of certain terms in various places in the specification, described herein, are for illustration and should not be construed as limiting.

Reference in the specification to “one embodiment,” “preferred embodiment,” “an embodiment,” or “embodiments” means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the disclosure and may be in more than one embodiment. The appearances of the phrases “in one embodiment,” “in an embodiment,” “in embodiments,” “in alternative embodiments,” “in an alternative embodiment,” or “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment or embodiments. The terms “include,” “including,” “comprise,” and “comprising” shall be understood to be open terms and any lists that follow are examples and not meant to be limited to the listed items.

Definitions

As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the context clearly dictates otherwise.

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present technology. It will be apparent, however, to one skilled in the art that embodiments of the present technology may be practiced without some of these specific details. The techniques introduced here can be embodied as special-purpose hardware (e.g. circuitry), as programmable circuitry appropriately programmed with software and/or firmware, or as a combination of special-purpose and programmable circuitry. Hence, embodiments may include a machine-readable medium having stored thereon instructions which may be used to program a computer (or other electronic devices) to perform a process. The machine-readable medium may include, but is not limited to, floppy diskettes, optical disks, compacts disc read-only memories (CD-ROMs), magneto-optical disks, ROMs, random access memories (RAMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), magnetic or optical cards, flash memory, or other type of media/machine-readable medium suitable for storing electronic instructions.

As used herein, the term “muscle activation sensor” refers to any sensor which can measure electrical activity in muscles in response to a nerve's stimulation of the muscle. For ease of reference, the exemplary embodiment described herein refers to electromyography (“EMG”), but this description should not be interpreted as exclusionary of other muscle activation sensors.

As used herein, the term “communicatively coupled” may refer to any coupling mechanism known in the art, such that at least one electrical signal may be transmitted between one device and one alternative device. Communicatively coupled may refer to Wi-Fi, Bluetooth, wired connections, wireless connection, and/or magnets. For ease of reference, the exemplary embodiment described herein refers to Wi-Fi and/or Bluetooth, but this description should not be interpreted as exclusionary of other electrical coupling mechanisms.

As used herein, the term “about” or “roughly” means approximately or nearly and in the context of a numerical value or range set forth means ±15% of the numerical.

All numerical designations, including ranges, are approximations which are varied up or down by increments of 1.0, 0.1, 0.01 or 0.001 as appropriate. It is to be understood, even if it is not always explicitly stated, that all numerical designations are preceded by the term “about”. It is also to be understood, even if it is not always explicitly stated, that the compounds and structures described herein are merely exemplary and that equivalents of such are known in the art and can be substituted for the compounds and structures explicitly stated herein.

Wherever the term “at least,” “greater than,” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

Wherever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 1, 2, or 3 is equivalent to less than or equal to 1, less than or equal to 2, or less than or equal to 3.

Variable Resistance Exercise System

The present disclosure pertains to a variable resistance exercise system configured to be temporarily affixed to at least one appendage of a user (e.g., an arm and/or a leg). In an embodiment, the variable resistance exercise system may have a mechanical damper, such that the variable resistance exercise system may be configured to provide resistance at least one targeted joint of the at least one appendage of the user, independent of the resistance level at any alternative joint. In this manner, in this embodiment, by focusing on the target joint, the mechanical dampening may prevent the variable resistance exercise system from being impacted by resistance provided naturally and/or synthetically by any neighboring joint. In addition, in this embodiment, the resistance may be speed-dependent and/or bi-directional—for example, a drag force that a user may experience in hydrotherapy—therefore relieving excessive strain applied on at least one alternative joint and/or at least one muscle of the user during the training.

Additionally, the variable resistance exercise system may comprise manually adjustable resistance. As such, in an embodiment, the variable resistance exercise system may include but is not limited at least one unique setting levels, such that the at least one unique setting level may comprise a resistance having a range from 0 Newton-meter (hereinafter “Nm”) to at most 100 Nm. For example, in some embodiments, the variable resistance exercise system may comprise eight (8) unique setting levels, such that at least one of the eight unique setting levels has a variable resistance having a range of 0 Nm to 16.6 Nm. Additionally, in an embodiment, the user may control the setting level, via manual input and/or at least one user interface of a computing device associated with the variable resistance exercise system, such that when the input is received from the user, the variable resistance exercise system may be configured to modulate and vary an intensity of at least one exercise (e.g., bicep curl and/or leg extension) provided by the variable resistance exercise system. As such, in this embodiment, the computing device may comprise at least one processor communicatively coupled to at least one sensor disposed about the variable resistance exercise system.

Another feature of the present disclosure is that the variable resistance exercise system may allow the user to cease any and/or all motion while experiencing no restorative forces. In an embodiment, the variable resistance exercise system may comprise at least one resistance-inducing mechanism and/or component including but not limited to at least one linear damper, at least one rotary damper, at least one cable and/or belt, and/or at least one pulley. For example, in some embodiments, multiple rotary dampers may be connected in parallel. In this manner, in these other embodiments, the variable resistance exercise system may allow the user to manually adjust the level of resistance.

FIG. 1 , in conjunction with FIGS. 2-4 , depict the variable resistance exercise system 100, according to an embodiment of the present disclosure. As such, in an embodiment, variable resistance exercise system 100 may comprise a base configured to be temporarily affixed to a top brace 126 and a bottom brace 128, such that variable resistance exercise system 100 may be configured to capture at least one joint (e.g., elbow and/or knee) movement of at least one appendage (e.g., arm and/or leg) of the user. As shown in FIG. 1 , FIG. 2 , and FIG. 3 , in an embodiment, in addition to top brace 126 and/or bottom brace 128, variable resistance exercise system 100 may also comprise an exercise apparatus 142, including but not limited to a base, a first pulley 102, a second pulley 104, and a third comprise a pulley 106, a first mechanical damper 112, a second mechanical damper 114, and a third mechanical damper 116, the at least one belt 108, and/or at least one bearing 124. In this manner, first pulley 102, second pulley 104, and/or third pulley 106, may be disposed upon base 110, such first pulley 102 may be in mechanical communication with second pulley 104 and/or third pulley 106, and vice versa. Furthermore, in this embodiment, first pulley 102, second pulley 104, and third pulley 106, may be in mechanical communication with top brace 126 and/or bottom brace 128.

As shown in FIG. 4 , in conjunction with FIGS. 1-3 and FIG. 5 , in an embodiment, the at least one mechanical damper 112, 114, and 116 of exercise apparatus 142 may be referred to as large, medium, and small (hereinafter “L, M, and S”), respectively, and/or may be configured to insert and/or temporarily couple at least one exercise key 118, 120, 122 complimentary to at least one chamber of the at least one mechanical damper 112, 114, 116. In this manner, a first exercise key 118 (hereinafter “large key 118”) may be configured to complimentary couple to large mechanical damper 112, a second exercise key 120 (hereinafter “medium key 120”) may be configured to complimentary couple to medium mechanical damper 114, as such, a third exercise key 122 (hereinafter “small key 122”) may be configured to complimentary couple to small mechanical damper 116, in accordance with the respective sizes and/or damping coefficients of the at least one exercise key, 118, 120, 122. In this embodiment, when the user engages with exercise apparatus 142 of variable resistance exercise system 100, large damper 112, medium damper 114, and/or small damper 116 may be configured may be configured to input a resistive force upon first pulley 102, a second pulley 104, and/or a third pulley 106, respectively, such that first pulley 102, a second pulley 104, and/or a third pulley 106 may be configured to input a resistive force against top brace 126 and/or bottom brace 128, providing resistance against movement of the at least one appendage (arm and/or leg) around the at least one joint (e.g., elbow and/or joint).

As described above, in an embodiment, exercise apparatus 142 of variable resistance exercise system 100 may also comprise at least one pulley 102, 104, 106, at least one exercise key 118, 120, 122, at least one belt 108, at least one mechanical damper 112, 114, 116, base 110, and/or at least one bearing 124. In addition, as shown in FIGS. 1-3 , in an embodiment, base 110, at least one pulley 102, 104, 106, at least one mechanical damper 112, 114, 116, and at least one exercise key 118, 120, 122, may comprise and/or may be configured to be fabricated with at least one of the following, Polylactic Acid (hereinafter “PLA”), metal (e.g., copper and/or iron), polyethylene, 3D printer material, and/or any material known in the art comprising PLA-like characteristics and/or properties. Furthermore, in some embodiments, the at least one pulley 102, 104, 106 and/or the at least one belt 108 may comprise and/or may be configured to be fabricated and/or designed using a 3D printer (e.g., Raise 3D Pro2 and/or Raise 3D Pro 3), such that the at least one pulley and/or belt 108 may be configured to withstand and/or transfer a resistive force to top brace 126 and/or bottom brace 128.

Additionally, as shown in FIGS. 1-5 , in an embodiment, the at least one pulley 102, 104, 106 of exercise apparatus 142 may comprise the same dimensions, such that variable resistance exercise system 100 may be configured to maintain a motion transmission ratio having a range of at least 1:5 to at most 5:1. For example, in some embodiments, variable resistance exercise system 100 may be configured to maintain a motion transmission ratio of 1:1. In an embodiment, as shown in FIG. 1 , in conjunction with FIGS. 3-5 , at least one mechanical damper 112, 114, 116, may be shaped in a polygonal form (e.g., a square, a circle, a pentagon, and/or a hexagon), such that at least one opening 132, 134, 136 of the at least one mechanical damper 112, 114, 116, respectively, may be complimentary of the respective at least one exercise key 118, 120, 122. In this manner, in some embodiments, the at least one opening 132, 134, 136 of at least one mechanical damper 112, 114, 116, may be configured to be removed and/or replaced with at least one alternative opening 132, 134, 136, such that the at least one alternative opening 132, 134, 136 may be complimentary of the respective at least one exercise keys 118, 120, 122 (e.g., a square opening to a circle opening).

In an embodiment, as shown in FIG. 4 and FIG. 5 , the at least one mechanical damper 112, 114, 116 of exercise apparatus 142 may be configured to encompass the respective at least one exercise key 118, 120, 122, such that when the at least one exercise key 118, 120, 122 is disposed within the at least one mechanical damper 112, 114, 116, the at least one mechanical damper 112, 114, 116 may be configured to provide resistance to the variable resistance exercise system. Additionally, in some embodiments, when inserted within the respective at least one mechanical damper 112, 114, 116, the at least one exercise key 118, 120, 122, may be configured to be flush with the at least one mechanical damper 112, 114, 116, such that the at least one opening 132, 134, 136 of the at least one mechanical damper 112, 114, 116 may be seamless with a top surface of the at least one exercise key 118, 120, 122. In addition, in some embodiments, the at least one exercise key 118, 120, 122 may comprise and/or be configured to be manufactured with at least one of the following be nylon, rubber, polyester, and/or any material known in the art which may provide a resistive force (e.g., a friction force and/or a gravitational force).

Moreover, as shown in FIG. 1 , in conjunction with FIGS. 2-5 , the at least one pulley 102, 104, 106 of exercise apparatus 142 of variable resistance exercise system 100 may be configured to be disposed on base 110, such that the at least one pulley 102, 104, 106 may form an triangle formation, including but not limited to an isosceles triangle, an equilateral triangle, an obtuse triangle, and/or any triangle formation known in the art. Accordingly, the at least one pulley 102, 104, 106 (e.g., first pulley 102, second pulley 104, and/or third pulley 106) may be connected via at least one belt 108 (e.g., two timing belts), such that that the at least one belt 108 may be configured to join the at least one pulley 102, 104, 106 to at least one alternative pulley 102, 104, 106 disposed on base 110. In this manner, as shown in FIG. 1 and FIG. 3 , in this embodiment, each pulley 102, 104, 106 may be configured to be attached to base 110 via at least one bearing 124 (e.g., Ball Bearing, Sealed, for ⅜″ Shaft Diameter) and/or at least one shaft 130. As such, as shown in FIG. 3 , the at least one pulley 102, 104, 106 may be configured to be inserted in a groove in base 110, such that the at least one pulley 102, 104, 106 may be configured to temporarily affixed to base 110 via a fastening mechanism. In some embodiments, the at least one pulley 102, 104, 106 may temporarily affix to base 110, such that a top surface of base 110 seamlessly abuts a bottom surface of the at least one pulley 102, 104, 106.

In addition, in an embodiment, the at least one mechanical damper 112, 114, 116 may be temporarily affixed to base 110 above their respective pulleys 102, 104, 106 through at least one fastening mechanism disposed within at least one shaft 130. For example, large damper 112 may be aligned over first pulley 102, such that large key 118 may be disposed within large damper 112, imparting a resistive force onto first pulley 102, via large damper 112.

Furthermore, as shown in FIG. 3 , in conjunction with FIGS. 1-2 and FIG. 4 , in an embodiment, the at least one bearing 124 and/or the at least one chamber of the at least one mechanical damper 112, 114, 116 of exercise apparatus 142 may be configured to traverse and/or be disposed at a bottom surface of the at least one pulley 102, 104, 106. In some embodiments, the at least one mechanical damper 112, 114, 116 may be aligned with the at least one pulley 102, 104, 106, respectively, such that the at least one mechanical damper 112, 114, 116 may be configured to engage the at least one pulley 102, 104, 106, respectively, by inserting the at least one exercise key 118, 120, 122, from the at least one opening 132, 134, 136. As such, in this embodiment, variable resistance exercise system 100 may be configured to apply at least one level of resistance and/or at least one alternative level of resistance through engaging and/or disengaging at least one mechanical damper 112, 114, 116, via inserting the at least one exercise key 118, 120, 122 into the at least one opening 132, 134, 136 of the at least one mechanical damper 112, 114, 116.

As shown in FIG. 4 , in an embodiment, as described above, first pulley 102 and/or large damper 112 may be configured to be aligned with the elbow joint center of the user, when the user attached variable resistance exercise system 100 to their at least one upper appendage (e.g., arm). As such, in this embodiment, variable resistance exercise system 100 may be configured to capture the motion of the elbow. In this manner, as shown in FIG. 5 , in an embodiment, Additionally, as shown in FIG. 3 , first pulley 102 and/or large damper 112 may be configured to be aligned with the knee joint center of the user, when the user attached variable resistance exercise system 100 to their at least one lower appendage (e.g., leg). As such, in this embodiment, variable resistance exercise system 100 may be configured to capture the motion of the knee.

FIG. 4 , in conjunction with FIGS. 1-3 , depicts a perspective view of variable resistance exercise system 100, according to an embodiment of the present disclosure. In an embodiment, variable resistance exercise system 100 may comprise top brace 126 and bottom brace 126 in mechanical communication with the at least one pulley 102, 104, 106, such that the at least one mechanical damper may input a resistive force against any force provided by user via top brace 126 and/or bottom brace 128 of variable resistance exercise system 100. In this embodiment, top brace 126 and/or bottom brace 128 may comprise at least one bar 138 and/or at least one cuff 140. In this manner, the at least one cuff 140, top brace 126, and/or bottom brace 128 may comprise and/or may be configured to be fabricated from at least one of the following including thermoplastic (e.g., acrylonitrile butadiene styrene (“ABS”)), metal (e.g., copper and/or iron), polyethylene, and/or any material known in the art with thermoplastic-like characteristics and/or properties. Additionally, in this embodiment, the at least one bar 138 of top brace 126 may be in mechanical communication with the at least one pulley 102, 104, 106 and/or at least one alternative bar 138 of bottom brace 128, such that variable resistance exercise system 100 may provide an acceptable range of motion for the user during use. Moreover, in some embodiments, the at least one bar 138 may comprise and/or may be configured to be fabricated from at least one of the following including aluminum, iron, bronze, tin, brass, zinc, and/or any other metal known in the art which may provide sturdiness without adding excessive weight.

In an embodiment, as shown in FIGS. 4-5 , the at least one bar 138 may be disposed about at least a portion of a top surface of top brace 126 and/or bottom brace 128, such that top brace 126 and/or bottom brace 128 may be molded to conform to the at least one appendage (e.g., arm and/or leg) of the user. Additionally, as shown in FIGS. 4-5 , in this embodiment, the at least one cuff 140 of top brace 126 and/or bottom brace 128 may be configured to cinch top brace 126 and/or bottom brace 128 around the at least one appendage of the user, via at least one ratchet mechanism disposed about at least a portion of the top brace 126 and/or bottom brace 128 of variable resistance exercise system 100.

Moreover, as shown in FIG. 6A-7B, in conjunction with FIGS. 1-3 , in an embodiment, variable resistance exercise system 100 may comprise at least one muscle activation sensor. As such, in an embodiment, the at least one muscle activation sensor may be temporarily affixed to variable resistance exercise system 100, such that the at least one muscle activation sensor may be configured to detect and/or transmit a muscle activation of the at least one appendage of the user to the computing device associated with variable resistance exercise system 100. In this embodiment, the at least one muscle activation sensor may also be configured to conform to the user wearing the variable resistance exercise system. Accordingly, the muscle activation sensor may detect the following exercise data, including but not limited to the weight, height, heart rate, and/or an age of the user.

Additionally, as shown in FIGS. 6A-7B, in conjunction with FIGS. 1-3 , in an embodiment, variable resistance exercise system 100 may also include at least one inertial measurement sensor. In this manner, in this embodiment, the at least one inertial measurement sensor may be configured to track, monitor, and/or transmit additional exercise data (e.g., movement of the at least one appendage of the user (e.g., speed of joint motion), the amount of torque conveyed on the variable resistance exercise system by the user and/or the amount of resistive force provided by resistive force provided by the at least one mechanical damper 112, 114, 116 to the at least one pulley 102, 104, 106) to a display device associated with computing device of variable resistance exercise system 100, via the at least one processor.

Furthermore, in an embodiment, variable resistance exercise system 100 may be configured to control a speed of joint motion by the user in order to prevent unintended injury to a user, via manual input by the user and/or the at least one processor of the computing device. Accordingly, in this embodiment, the speed of joint motion may be controlled at specific intervals within the exercise, including but not limited to, full extension of the elbow, the start of flexion, maximum flexion, the start of extension, and/or full extension.

As such, in this embodiment, when the speed of joint motion exceeds a predetermined value (e.g., at least 20 mm/s) the at least one processor of variable resistance exercise system 100 may be configured to transmit at least one signal indicative of resistive application, such that at least a portion of resistive force may be provided by the at least one mechanical damper 112, 114, 116, such that the user may be prevented and/or inhibited from continuing use of variable resistance exercise system 100. Accordingly, variable resistance exercise system 100 may be configured to automatically engage and/or disengage the at least mechanical damper 112, 114, 116 based on user input and/or the at least one processor. In addition, in some embodiments, variable resistance exercise system 100 may be configured to receive at least one input from at least one third-party (e.g., a doctor and/or a personal trainer), via the at least one user interface and/or at least one alternative user interface communicatively coupled to the exercise apparatus (e.g., wireless communication, wired communication, Bluetooth, and/or Radio Waves), such that the variable resistance exercise system may be configured to automatically engage and/or disengage at least one mechanical damper 112, 114, 116, accordingly.

Method of Use

Referring now to FIG. 25 , in conjunction with FIGS. 1-24 , a method is depicted for exercising at least one muscle group of a user using variable resistance exercise system 100. The steps delineated are merely exemplary of a preferred order of exercising at least one muscle group of a user using variable resistance exercise system 100. The steps may be carried out in another order, with or without additional steps including therein. Additionally, the steps may be carried out with alternative embodiments of the variable resistance exercise system, as contemplated in the above description.

As shown in FIG. 25 , in conjunction with FIGS. 1-24 , in an embodiment, the method 200 for exercising at least one muscle group of a user using variable resistance exercise system 100 begins at step 202, affixing variable resistance exercise system 100 onto at least one appendage of the user to focus on resistance at a single joint (e.g., an elbow and/or a knee). Accordingly, in this embodiment, variable resistance exercise system 100 may comprise a computing device affixed to at least one portion of variable resistance exercise system 100. Additionally, the computing device may comprise at least one processor. Next, at step 204, at least one exercise key 118, 120, 122 may be inserted into at least one mechanical dampener 112, 114, 116 in mechanical communication with at least one pulley 102, 104, 106 of variable resistance exercise system 100.

Accordingly, referring again to FIG. 25 , at step 206, as the user is performing an exercise, which may comprise flexion and/or extension of the appendage of the user, variable resistance exercise system 100 may be configured to provide at least one resistive force, such that a force exerted by the user while performing the exercise is increased. Further, in this embodiment, during and/or after the user performs the exercise, at step 208, at least one sensor (e.g., muscle activation sensor and/or inertial measurement sensor) communicatively coupled to the at least one processor of variable resistance exercise system 100 may be configured to transmit exercise data collected to a display device associated with variable resistance exercise system 100. In addition, in this embodiment, the at least one processor may be configured to filter and/or apply at least one equation and/or algorithm to the exercise data, such that a maximum torque required to overcome a damping coefficient of variable resistance exercise system 100 may be calculated. Finally, at step 210, variable resistance exercise system 100 may be configured to display the exercise data and/or the calculated maximum torque on a display device associated with the computing device of variable resistance exercise system. As such, in this embodiment, the display device may be configured to provide the user with the exercise data, via visual means (e.g., a graphical-user interface), auditory means (e.g., a speaker), and/or tactile means (e.g., a handheld controller comprising a vibration motor configured to output Morse Code, and/or the computing device communicatively coupled to a braille embosser). Additionally, in some embodiments, variable resistance exercise system 100 may be configured to transmit a notification to the user indicative of the maximum torque required and/or any additional torque force required to overcome the damping coefficient of variable resistance exercise system 100.

The following examples are provided for the purpose of exemplification and are not intended to be limiting.

EXAMPLES Example 1

Determination of Required Torque for Bicep Flexion

As shown in FIGS. 6A-6B, several trials were conducted on a user to determine the required torque to overcome the dampening coefficient for bicep flexion at eight different resistance levels. A microcontroller (Arduino Uno, Somerville, MA), connected to a soundboard (Adafruit Audio FX Sound Board, Adafruit, New York, NY), was installed to serve as a metronome to control this tempo across all participants during the experiment. The cadence was based on the ability of the volunteer to flex and contract their arm with all the keys (SML) engaged in the system, providing the highest resistance (6.75±2.3 seconds). The same tempo was maintained for the rest of the exercises. The data collected from each participant was saved in the MR3 software database (Noraxon), sampled at 2000 Hz for EMG and 200 Hz for IMUs. The data was exported in CSV format, then processed and analyzed using MATLAB (R2021b; MathWorks, Natick, MA). Filtering of the EMG data started by applying a 4^(th)-order bandpass filter with cut-off frequencies of 20 and 450 Hz. Subsequently, the data was rectified, followed by a 4^(th)-order low-pass filtering with a low-pass frequency of 6 Hz. The processed data was time normalized to 0-100% cycle using the tempo signal generated from Arduino. In addition, as shown in FIGS. 6A-6B, the peak EMG during maximum voluntary contraction (MVC) for bicep flexion was collected in 2 sets of 3 repetitions of MVC testing. The MVC was used to normalize the EMG data subject-wise. The normalized mean of peak EMG and integrated EMG for each configuration was averaged over the three repetitions and later used to calculate the mean and standard deviation of the user.

The means and standard deviation of the user for biceps muscle activation are shown in FIGS. 8-10 , respectively. As shown in FIG. 8 , the peak EMG of the user's biceps proportionally varies as the level of resistance changes from high to low. In this same manner, as shown in FIG. 9 , the integrated EMG (“iEMG”) of the user's biceps also proportionally varies as the level of resistance changes from high to low. The normalized peak biceps EMG at the highest resistance (SML), as shown in FIG. 10 , was 0.858, which is 2.68 times greater than the Not Active (NA) case. The normalized integrated EMG (iEMG) of biceps shows similar trends; the highest iEMG at SML (27.924), is 2.45 times greater than NA (11.392). Moreover, as shown in FIG. 10 , the user average linear envelope of EMG over 100% elbow flexion/extension cycle illustrates the gradual increase in muscle activation from the lowest resistance (NA) to the highest (SML). The first half (0 to 50% cycle) indicates the elbow flexion phase, and the second half (50% to 100% cycle) specifies the elbow extension phase.

Example 2

Determination of Required Torque for Triceps Flexion

As shown in FIGS. 7A-7B, several trials were conducted on a user to determine the required torque to overcome the dampening coefficient for triceps flexion at eight different resistance levels. A microcontroller (Arduino Uno, Somerville, MA), connected to a soundboard (Adafruit Audio FX Sound Board, Adafruit, New York, NY), was installed to serve as a metronome to control this tempo across all participants during the experiment. The cadence was based on the ability of the volunteer to flex and extend their arm with all the keys (SML) engaged in the system, providing the highest resistance (6.75±2.3 seconds). The same tempo was maintained for the rest of the exercises. The data collected from each participant was saved in the MR3 software database (Noraxon), sampled at 2000 Hz for EMG and 200 Hz for IMUs. The data was exported in CSV format, then processed and analyzed using MATLAB (R2021b; MathWorks, Natick, MA). Filtering of the EMG data started by applying a 4^(th)-order bandpass filter with cut-off frequencies of 20 and 450 Hz. Subsequently, the data was rectified, followed by a 4^(th)-order low-pass filtering with a low-pass frequency of 6 Hz. The processed data was time normalized to 0-100% cycle using the tempo signal generated from Arduino. In addition, as shown in FIGS. 7A-7B, the peak EMG during maximum voluntary contraction (MVC) for triceps flexion was collected in 2 sets of 3 repetitions of MVC testing. The MVC was used to normalize the EMG data subject-wise. The normalized mean of peak EMG and integrated EMG for each configuration was averaged over the three repetitions and later used to calculate the mean and standard deviation of the user.

The means and standard deviation of the user for triceps muscle activation are shown in FIGS. 11-13 , respectively. The results are reasonably similar to Example 1 as provided above. As shown in FIG. 11 , as the resistance configurations were switched from the highest (SML) to the lowest (NA), the triceps muscle activation decreased, except the peak EMG during L and M conditions were higher than SL and SM. However, this did not affect the integrated EMG results of the triceps. Accordingly, as shown in FIG. 12 , the integrated EMG results of the triceps showed a constant decrease in the value from SML to NA. This could be due to inconsistent speed in these particular conditions from some subjects or could be related to fatigue effects. Nevertheless, the results indicate that the intended function of the variable resistance exercise system was met—the ability to adjust and apply variable resistance at a joint—as seen from the changes in the flexor and extensor muscle activations corresponding to different resistance levels.

Additionally, the normalized peak biceps EMG at the highest resistance (SML), as shown in FIG. 13 , the user average linear envelope of EMG over 100% elbow flexion/extension cycle illustrates the gradual increase in muscle activation from the lowest resistance (NA) to the highest (SML). The first half (0 to 50% cycle) indicates the elbow flexion phase, and the second half (50% to 100% cycle) specifies the elbow extension phase.

TABLE 1, provided below, represents a compilation of experimental data (e.g., biceps and triceps flexion) from several trials performed on users. Accordingly, TABLE 1 shows the resistance level (e.g., damping coefficient) and the maximum torque required to overcome the specified damping coefficient for eight different resistance levels through dissimilar combinations. As shown in FIGS. 1-3 , in some embodiments, the highest resistance level may be obtained when all the three exercise keys 118, 120, 122 are inserted, engaging small damper 116, medium damper 114, and large damper 112 (hereinafter “SML”). The lowest resistance may also be obtained when no damper is actively engaged, allowing the user full range of motion without requiring overcoming the damping coefficient.

TABLE 1 Damping Max. Torque Coefficient @ 300°/s Configurations [NM*s/rad] [N-m] SML S + M + L 3.16 16.6 ML M + L 2.74 14.3 SL S + L 1.98 10.4 SM S + M 1.60 8.4 L Large Damper 1.56 8.1 M Medium Damper 1.18 6.2 S Small Damper 0.42 2.2 NA Not Active 0 0

Example 3

Muscle Hypertrophy Assessment

The experiment consisted of three in-lab assessment sessions (BL, S1, and S2) and an 8-week long training session utilizing the variable resistance exercise system. Twelve healthy untrained male subjects (22.6±4.2 years old) completed the in-lab assessment session. The in-lab assessment sessions collected data from the subjects related to muscle mass and strength through isometric and isokinetic exercise using a dynamometer, ultrasound to measure muscle size (thickness at rest, thickness during maximal voluntary isometric contraction (hereinafter “MVIC”), cross-sectional area), and bioimpedance measurement. The assessments took place before the training (pre-training), at the mid-point (mid-training), and after completing the training (post-training), as shown in FIG. 14 .

Following the baseline (BL) session, the subject completed 24 single-day training sessions (1 hour long) in the lab, three days a week, for 8 weeks. The subjects were asked to fill out the following forms. First, Health and Injury Information, along with the Exercise Testing Screening Tool, was sent via email for screening and returned to the research team via email. Once their eligibility to participate was confirmed, the participant was scheduled for the first in-lab assessment session (BL). The participants were asked to bring/wear shorts and a short-sleeve shirt to/on all assessment sessions. During their first visit (BL), the informed consent form was administered to the participants. The research team explained the procedures, potential risks, and benefits and answered any questions the subjects had. Only after the subject agreed to participate by signing the informed consent form, they became subjects, and the BL assessment procedure commenced. The research team took pictures, videos, or both of the sessions after verbal consent from the subject was given.

The statistical analysis generated graphs for elbow and knee results, as shown in FIGS. 15-24 , where we can see that across three speeds tested for isokinetic torque, the main effect and pairwise comparisons revealed statistical significance between BL-S2 for both elbow and knee flexion/extension as represented by the asterisk(s) (*) which represent the p values (*p<0.05, **p<0.01, and ***p<0.001). Please refer to TABLE 4 and TABLE 5 for more in depth results and p values. There was a statistical significance in almost all the results except elbow flexion at 75 degrees/sec for both average peak torque and average peak torque over skeletal muscle mass, as shown in FIGS. 15-19 . For isometric torque, statistical significance was found in both elbow and knee flexion/extension between BL and S2, as shown in FIGS. 15-24 .

TABLE 2 Main Pairwise Group Mean ± Standar Deviation BL S1 S2 Effect (p) Comparison (p) E 75 deg/s 1.02 ± 0.12 1.23 ± 0.20 1.53 ± 0.35 1.20e−05 1^(st)-2^(nd) 2.01e−04 Peak TQ/ 1^(st)-3^(rd) 7.00e−07 SMM 2^(nd)-3^(rd) 2.40e−02 90 deg/s 1.07 ± 0.17 1.29 ± 0.22 1.61 ± 0.38 1.14e−03 1^(st)-2^(nd) 2.00e−02 Peak TQ/ 1^(st)-3^(rd) 6.56e−04 SMM 2^(nd)-3^(rd) 2.80e−02 120 deg/s 1.04 ± 0.13 1.29 ± 0.16 1.56 ± 0.37 1.15e−03 1^(st)-2^(nd) 6.00e−03 Peak TQ/ 1^(st)-3^(rd) 6.56e−04 SMM 2^(nd)-3^(rd) 1.14e−01 Isometric Peak TQ/ 1.20 ± 0.28 1.30 ± 0.29 1.65 ± 0.38 2.39e−04 1^(st)-2^(nd) 1.09e−01 SMM 1^(st)-3^(rd) 3.38e−04 2^(nd)-3^(rd) 9.00e−03 Flexion Isokinetic 75 deg/s 0.86 ± 0.18 0.99 ± 0.22 1.17 ± 0.30 3.56e−02 1^(st)-2^(nd) 1.14e−01 Peak TQ/ 1^(st)-3^(rd) 1.70e−02 SMM 2^(nd)-3^(rd) 1.98e−01 90 deg/s 0.85 ± 0.16 1.03 ± 0.18 1.17 ± 0.29 2.00e−03 1^(st)-2^(nd) 6.00e−03 Peak TQ/ 1^(st)-3^(rd) 2.00e−03 SMM 2^(nd)-3^(rd) 1.51e−01 120 deg/s 0.85 ± 0.24 0.98 ± 0.14 1.15 ± 0.25 6.97e−04 1^(st)-2^(nd) 4.00e−03 Peak TQ/ 1^(st)-3^(rd) 4.00e−03 SMM 2^(nd)-3^(rd) 7.50e−02 Isometric Peak 1.21 ± 0.31 1.35 ± 0.44 1.49 ± 0.40 1.80e−02 1^(st)-2^(nd) 2.23e−01 TQ/SMM 1^(st)-3^(rd) 2.00e−03 2^(nd)-3^(rd) 1.43e−01

TABLE 3 Main Pairwise Group Mean ± Standar Deviation BL S1 S2 Effect (p) Comparison (p) K E I 75 deg/s 3.24 ± 1.21 4.21 ± 1.16 4.77 ± 0.84 8.40e−06 1^(st)-2^(nd) 1.40e−02 Peak TQ/ 1^(st)-3^(rd) 1.64e−04 SMM 2^(nd)-3^(rd) 3.84e−04 90 deg/s 3.23 ± 1.29 4.08 ± 1.04 4.82 ± 0.96 3.72e−05 1^(st)-2^(nd) 2.80e−02 Peak TQ/ 1^(st)-3^(rd) 2.06e−04 SMM 2^(nd)-3^(rd) 3.00e−03 120 deg/s 3.05 ± 1.17 3.55 ± 1.32 4.52 ± 0.93 1.26e−04 1^(st)-2^(nd) 2.43e−01 Peak TQ/ 1^(st)-3^(rd) 7.78e−04 SMM 2^(nd)-3^(rd) 2.39e−04 Isometric Peak TQ/ 4.74 ± 1.56 5.09 ± 1.63 6.65 ± 1.77 1.00e−05 1^(st)-2^(nd) 3.91e−01 SMM 1^(st)-3^(rd) 1.16e−04 2^(nd)-3^(rd) 4.84e−04 Flexion Isokinetic 75 deg/s 2.31 ± 0.68 2.79 ± 0.57 3.18 ± 0.55 2.40e−06 1^(st)-2^(nd) 6.22e−04 Peak TQ/ 1^(st)-3^(rd) 9.33e−05 SMM 2^(nd)-3^(rd) 8.00e−03 90 deg/s 2.20 ± 0.85 2.78 ± 0.45 3.23 ± 0.47 4.90e−06 1^(st)-2^(nd) 5.00e−03 Peak TQ/ 1^(st)-3^(rd) 6.89e−05 SMM 2^(nd)-3^(rd) 4.00e−03 120 deg/s 2.08 ± 0.75 2.50 ± 0.74 3.06 ± 0.59 4.90e−06 1^(st)-2^(nd) 8.00e−03 Peak TQ/ 1^(st)-3^(rd) 1.10e−04 SMM 2^(nd)-3^(rd) 2.00e−03 Isometric Peak 2.40 ± 0.88 2.53 ± 0.53 3.15 ± 0.70 1.09e−04 1^(st)-2^(nd) 3.14e−01 TQ/SMM 1^(st)-3^(rd) 2.00e−03 2^(nd)-3^(rd) 3.05e−04

In conclusion, a speed-dependent, bidirectional, and adjustable resistance training tool has been designed, fabricated, and evaluated for its functionality and efficacy. The 8 different resistances could be modulated, and an increase in muscle strength, or hypertrophy, was achieved through 8 week-long training using the variable resistance exercise system.

The advantages set forth above, and those made apparent from the foregoing description, are efficiently attained. Since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

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All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. 

What is claimed is:
 1. A variable resistance exercise system comprising: at least one brace configured to conform to an appendage of a user; and an exercise apparatus configured to be disposed about a portion of a surface of the at least one brace aligning with a predetermined joint of a user, the exercise apparatus being in mechanical communication with the at least one brace, wherein the exercise apparatus further comprises: a base; a plurality of pulleys configured to be temporarily affixed to the base; at least one belt in mechanical communication with the plurality of pulleys, wherein the at least one belt is configured to encompass the plurality of pulleys; a plurality of mechanical dampers disposed about at least a portion of the plurality of pulleys; and wherein the plurality of mechanical dampers are configured to provide a damping coefficient upon the plurality of pulleys, thereby increasing a force required to translate the at least one belt about the plurality of pulleys.
 2. The variable resistance exercise system of claim 1, wherein the exercise apparatus further comprises a plurality of exercise keys, wherein the each one of the plurality of exercise keys is configured to be disposed within an opening of each respective mechanical damper of the plurality of mechanical dampers.
 3. The variable resistance exercise system of claim 2, wherein when at least one of the plurality of exercise keys is disposed within at least one of the plurality of mechanical dampers, the at least one mechanical damper is configured to provide a damping coefficient, thereby increasing a force required to operate the plurality of pulleys.
 4. The variable resistance exercise system of claim 1, wherein each of the plurality of pulleys comprises at least one ball bearing, wherein the at least one ball bearing is configured to allow the plurality of pulleys to rotate about the base of the exercise apparatus.
 5. The variable resistance exercise system of claim 1, wherein the plurality of mechanical dampers are selected from a group consisting of a small mechanical damper, a medium mechanical damper, a large mechanical damper, and a combination of thereof.
 6. The variable resistance exercise system of claim 2, wherein the plurality of exercise keys are selected from a group consisting of a small exercise key, a medium exercise key, a large exercise key, and a combination of thereof.
 7. The variable resistance exercise system of claim 6, wherein the small mechanical damper is configured to provide a lower damping coefficient than the medium mechanical damper, the large mechanical damper, or both.
 8. The variable resistance exercise system of claim 2, further comprising: a computing device having at least one processor communicatively coupled to at least one sensor, the at least one sensor configured to detect an exertion from at least one muscle group in mechanical communication with the predetermined joint, wherein the at least one sensor is disposed about at least one portion of the at least one brace, the exercise apparatus, or both; and an electronic circuity disposed within the base of exercise apparatus, the electronic circuity configured to selectively supply the electronic current to the computing device, the at least one sensor, or both.
 9. The variable resistance exercise system of claim 8, wherein exercise data consists of a group selected from a total amount exertion by a targeted muscle group disposed about the predetermined joint of the user during the plurality of exercises, a weight of the user, a total amount of mechanical dampers comprising an exercise key, a height of the user, an age of the user, a gender of the user, and a combination of thereof.
 10. The variable resistance exercise system of claim 9, wherein subsequent to receiving the exercise data from the at least one sensor, the at least one processor is configured to cause the electronic circuity to supply an electric current to a display device associated with the computing device, whereby the display device is configured to provide the exercise data to the user.
 11. The variable resistance exercise system of claim 1, wherein the plurality of pulleys of the exercise apparatus are configured to be bi-directional.
 12. An exercise apparatus for providing variable resistance during an exercise, the exercise apparatus comprising: a base; a plurality of pulleys configured to be temporarily affixed to the base; at least one belt in mechanical communication with the plurality of pulleys, wherein the at least one belt is configured to encompass the plurality of pulleys; a plurality of mechanical dampers disposed about at least a portion of the plurality of pulleys; and wherein the plurality of mechanical dampers are configured to provide a damping coefficient upon the plurality of pulleys, thereby increasing a force required to translate the at least one belt about the plurality of pulleys.
 13. The exercise apparatus of claim 12, further comprising a plurality of exercise keys, wherein the each one of the plurality of exercise keys is configured to be disposed within an opening of each respective mechanical damper of the plurality of mechanical dampers.
 14. The exercise apparatus of claim 13, wherein when at least one of the plurality of exercise keys is disposed within at least one of the plurality of mechanical dampers, the at least one mechanical damper is configured to provide a damping coefficient, thereby increasing a force required to operate the plurality of pulleys.
 15. The exercise apparatus of claim 12, wherein each of the plurality of pulleys comprises at least one ball bearing, wherein the at least one ball bearing is configured to allow the plurality of pulleys to rotate about the base of the exercise apparatus.
 16. The exercise apparatus of claim 12, wherein the plurality of mechanical dampers are selected from a group consisting of a small mechanical damper, a medium mechanical damper, a large mechanical damper, and a combination of thereof.
 17. The exercise apparatus of claim 16, wherein the small mechanical damper is configured to provide a lower damping coefficient than the medium mechanical damper, the large mechanical damper, or both.
 18. A method of providing a variable resistance to a targeted muscle group at a predetermined joint of a user during a plurality of exercises, the method comprising: affixing a variable resistance exercise system to the user, the variable resistance exercise apparatus comprising: at least one brace configured to conform to an appendage of a user; and an exercise apparatus configured to be disposed about a portion of a surface of the at least one brace aligning with a predetermined joint of a user, the exercise apparatus being in mechanical communication with the at least one brace, wherein the exercise apparatus further comprises: a base; a plurality of pulleys configured to be temporarily affixed to the base; at least one belt in mechanical communication with the plurality of pulleys, wherein the at least one belt is configured to encompass the plurality of pulleys; a plurality of mechanical dampers disposed about at least a portion of the plurality of pulleys; and wherein the plurality of mechanical dampers are configured to provide a damping coefficient upon the plurality of pulleys, thereby increasing a force required to translate the at least one belt about the plurality of pulleys; engaging, via at least one of a plurality of exercises keys configured to be disposed within an opening of at least one respective mechanical damper of the plurality of mechanical dampers, at least one of the plurality of mechanical dampers, wherein the at least one of the plurality of mechanical dampers provides a damping coefficient on at least one of the plurality of pulleys, thereby increasing the required resistance to translate the at least one belt about the plurality of pulleys; and performing, via variable resistance exercise system, a plurality of exercises requiring flexion, extension, or both, of the targeted muscle group, wherein a resistive force is provided to the targeted muscle group based on a total amount of engaged mechanical dampers.
 19. The method of claim 18, wherein the variable resistance exercise system, further comprises: a computing device having at least one processor communicatively coupled to at least one sensor, wherein the at least one sensor is disposed about at least one portion of the at least one brace, the exercise apparatus, or both; and an electronic circuity disposed within the base of exercise apparatus, the electronic circuity configured to selectively supply the electronic current to the computing device, the at least one sensor, or both.
 20. The method of claim 19, further comprising the steps of: transmitting, via the at least one sensor, exercise data to a display device associated with the computing device of the variable resistance exercise system; and displaying, via the at least one processor, the exercise data on the display device, wherein the display device is configured to provide the exercise data to the user via visual means, auditory means, tactile means, and a combination of thereof. 